// 
// Copyright (c) 2006-2009 Ben Motmans
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// Author(s):
//    Ben Motmans <ben.motmans@gmail.com>
//

using System;
using System.IO;
using System.Text;
using System.Collections.Generic;
using System.Security.Cryptography;

namespace Anculus.Core
{
	/// <summary>
	/// 
	/// </summary>
	public static class Hash
	{
		public static ByteBuffer Md5File (string fileName)
		{
			if (fileName == null)
				throw new ArgumentNullException ("fileName");
			
			return CalculateFileHash (MD5.Create (), fileName);
		}
		
		public static ByteBuffer Md5 (ByteBuffer data)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (data.Length == 0)
				throw new ArgumentException ("data");
			
			return MD5.Create ().ComputeHash (data.Raw);
		}
		
		public static ByteBuffer Sha1File (string fileName)
		{
			if (fileName == null)
				throw new ArgumentNullException ("fileName");
			
			return CalculateFileHash (SHA1.Create (), fileName);
		}
		
		public static ByteBuffer Sha1 (ByteBuffer data)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (data.Length == 0)
				throw new ArgumentException ("data");
			
			return SHA1.Create ().ComputeHash (data.Raw);
		}
		
		public static ByteBuffer Sha256File (string fileName)
		{
			if (fileName == null)
				throw new ArgumentNullException ("fileName");
			
			return CalculateFileHash (SHA256.Create (), fileName);
		}
		
		public static ByteBuffer Sha256 (ByteBuffer data)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (data.Length == 0)
				throw new ArgumentException ("data");
			
			return SHA256.Create ().ComputeHash (data.Raw);
		}
		
		public static ByteBuffer Sha512File (string fileName)
		{
			if (fileName == null)
				throw new ArgumentNullException ("fileName");
			
			return CalculateFileHash (SHA512.Create (), fileName);
		}
		
		public static ByteBuffer Sha512 (ByteBuffer data)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (data.Length == 0)
				throw new ArgumentException ("data");
			
			return SHA512.Create ().ComputeHash (data.Raw);
		}
		
		//TODO: ripe MD ?
		
		private static ByteBuffer CalculateFileHash (HashAlgorithm algo, string fileName)
		{
			if (!File.Exists (fileName))
				return null;

			using (FileStream fs = new FileStream (fileName, FileMode.Open, FileAccess.Read)) {
				return new ByteBuffer (algo.ComputeHash (fs));
			}
		}
	}
}